Another question relating to synthetics in the rear axle of my Quadra Drive WK2: Is the 4 oz. Mopar friction modifier (04318060AB) the same thing that is in their 1 qt product with the modifier already in the gear oil(#68083381AA)? I was told by the parts guy that he wouldn't "risk" it because of the aluminum construction of my diff. He implied that the 4 oz. friction modifier additive was for the iron rear ends. In a nutshell, I want to add the 4 oz. to synthetic gear oil but I don't want to risk doing something when I'm not sure about what the effect might be. Any Mopar mechanics out there?

FYI, the Amsoil reference chart refers to the 1 qt. product in the rear end with no mention of the 4 oz. friction modifier.

Whether made out of iron, aluminum, or plastic it doesn't matter. The internals are always steel. If it calls for the friction modifier put it in, it shouldn't hurt anything unless it calls out for no friction modifier.

Another question relating to synthetics in the rear axle of my Quadra Drive WK2: Is the 4 oz. Mopar friction modifier (04318060AB) the same thing that is in their 1 qt product with the modifier already in the gear oil(#68083381AA)? I was told by the parts guy that he wouldn't "risk" it because of the aluminum construction of my diff. He implied that the 4 oz. friction modifier additive was for the iron rear ends. In a nutshell, I want to add the 4 oz. to synthetic gear oil but I don't want to risk doing something when I'm not sure about what the effect might be. Any Mopar mechanics out there?

FYI, the Amsoil reference chart refers to the 1 qt. product in the rear end with no mention of the 4 oz. friction modifier.

I'm not a Chrysler mechanic, but can tell you that a mod is a mod is a mod. As long as it is for hypoid gear (ring and pinion/ worm) service. The biggest difference is the label on the bottle. That and *maybe* a couple ppm of this or that.
In regards to Amsoil, there is a note to add friction modifier down in the notes of the product. However, next to the product list you will see a red note "2" which indicates that they recommend Mopar P/N 68083381AA with ELSD. I do not know why.AMSOIL Online Product Application Guide
EDIT- I just got an email back from Amsoil saying"The abbreviation ELSD is Limited Slip. AMSOIL SVG is recommended for use whether it has limited slip (ELSD) or not. The part number quoted is the OEM Limited Slip , which is not needed if the AMOIL is used."

Quote:

Originally Posted by Hercules

I thought Chrysler went to 75/140 synthetic is all the rear ends a few years back. I know that was the fill if you had the factory tow package. Also what came in the 5.7 LX rear ends.
The Mopar 75/140 gear lube is synthetic.

There has been much discussion on the forum regarding the oil specified in the owners manual vs. what shop manual says.

I spoke with someone at Amsoil today concerning the issue of friction modifiers in the ELSD rear axle of my WK2. He told me that their Extreme Gear 75W-90 gear oil DOES NOT need the friction modifier because it is already in the product. He also stated that this preoduct exceeds OEM specs and will not void any warranty. I'll give this a try.